At the present time, there are over 118,700 telecommunication towers in the United States. This figure only accounts for towers owned by domestic companies, excluding those towers owned by the government, military, or foreign entities. In addition to telecommunication towers, antennas and mounts are also installed on buildings, water towers, grain silos, smoke stacks, and other structures that provide the requisite elevation for propagating radio frequency (RF) or microwave (MW) signals. Commercial cellular towers typically range from 80 to 400 feet above ground level (AGL) in height, but have been known to be as short as 20 feet or as tall as 1,800 feet.
In order to obtain the required information for a structural analysis report, a measurement crew is traditionally employed to climb the tower with their measurement and recordation equipment. Each structural element, e.g., angles, pipes, and bolts, would be physically measured with the results being subsequently recorded. This measurement technique has several apparent deficiencies. The first deficiency relates to safety. This technique constitutes a high-risk work activity, ranked by industry watchdogs and the Occupational Safety and Health Administration (OSHA) as having the highest, or at a minimum within the top four highest, construction-based fatalities per 100,000 workers. Moreover, climbing crews are at risk for exposure to RF radiation and, therefore, there is a need to monitor RF exposure. The second deficiency relates to cost. Costs may include labor, training, equipment, climbing and safety certifications, infrastructure or equipment damage repairs or replacements, liability insurance, and workers' compensation. Finally, there may be compliance issues, such as relating to non-disturbance of endangered or protected wildlife species.
Currently-available non-physical solutions for mapping and measuring via optical or non-optical means cannot produce accuracies of less than 1.5 inches or 3 to 4 cm. Therefore, there exists a need for effective means to make the above-described measurements in a safe and more cost-effective manner while also achieving superior accuracy.